1Kernel driver sht3x 2=================== 3 4Supported chips: 5 6 * Sensirion SHT3x-DIS 7 8 Prefix: 'sht3x' 9 10 Addresses scanned: none 11 12 Datasheets: 13 - https://sensirion.com/media/documents/213E6A3B/63A5A569/Datasheet_SHT3x_DIS.pdf 14 - https://sensirion.com/media/documents/051DF50B/639C8101/Sensirion_Humidity_and_Temperature_Sensors_Datasheet_SHT33.pdf 15 16 * Sensirion STS3x-DIS 17 18 Prefix: 'sts3x' 19 20 Addresses scanned: none 21 22 Datasheets: 23 - https://sensirion.com/media/documents/1DA31AFD/61641F76/Sensirion_Temperature_Sensors_STS3x_Datasheet.pdf 24 - https://sensirion.com/media/documents/292A335C/65537BAF/Sensirion_Datasheet_STS32_STS33.pdf 25 26Author: 27 28 - David Frey <david.frey@sensirion.com> 29 - Pascal Sachs <pascal.sachs@sensirion.com> 30 31Description 32----------- 33 34This driver implements support for the Sensirion SHT3x-DIS and STS3x-DIS 35series of humidity and temperature sensors. Temperature is measured in degrees 36celsius, relative humidity is expressed as a percentage. In the sysfs interface, 37all values are scaled by 1000, i.e. the value for 31.5 degrees celsius is 31500. 38 39The device communicates with the I2C protocol. Sensors can have the I2C 40addresses 0x44 or 0x45 (0x4a or 0x4b for sts3x), depending on the wiring. See 41Documentation/i2c/instantiating-devices.rst for methods to instantiate the 42device. 43 44Even if sht3x sensor supports clock-stretch (blocking mode) and non-stretch 45(non-blocking mode) in single-shot mode, this driver only supports the latter. 46 47The sht3x sensor supports a single shot mode as well as 5 periodic measure 48modes, which can be controlled with the update_interval sysfs interface. 49The allowed update_interval in milliseconds are as follows: 50 51 ===== ======= ==================== 52 0 single shot mode 53 2000 0.5 Hz periodic measurement 54 1000 1 Hz periodic measurement 55 500 2 Hz periodic measurement 56 250 4 Hz periodic measurement 57 100 10 Hz periodic measurement 58 ===== ======= ==================== 59 60In the periodic measure mode, the sensor automatically triggers a measurement 61with the configured update interval on the chip. When a temperature or humidity 62reading exceeds the configured limits, the alert attribute is set to 1 and 63the alert pin on the sensor is set to high. 64When the temperature and humidity readings move back between the hysteresis 65values, the alert bit is set to 0 and the alert pin on the sensor is set to 66low. 67 68The serial number exposed to debugfs allows for unique identification of the 69sensors. For sts32, sts33 and sht33, the manufacturer provides calibration 70certificates through an API. 71 72sysfs-Interface 73--------------- 74 75=================== ============================================================ 76temp1_input: temperature input 77humidity1_input: humidity input 78temp1_max: temperature max value 79temp1_max_hyst: temperature hysteresis value for max limit 80humidity1_max: humidity max value 81humidity1_max_hyst: humidity hysteresis value for max limit 82temp1_min: temperature min value 83temp1_min_hyst: temperature hysteresis value for min limit 84humidity1_min: humidity min value 85humidity1_min_hyst: humidity hysteresis value for min limit 86temp1_alarm: alarm flag is set to 1 if the temperature is outside the 87 configured limits. Alarm only works in periodic measure mode 88humidity1_alarm: alarm flag is set to 1 if the humidity is outside the 89 configured limits. Alarm only works in periodic measure mode 90heater_enable: heater enable, heating element removes excess humidity from 91 sensor: 92 93 - 0: turned off 94 - 1: turned on 95update_interval: update interval, 0 for single shot, interval in msec 96 for periodic measurement. If the interval is not supported 97 by the sensor, the next faster interval is chosen 98repeatability: write or read repeatability, higher repeatability means 99 longer measurement duration, lower noise level and 100 larger energy consumption: 101 102 - 0: low repeatability 103 - 1: medium repeatability 104 - 2: high repeatability 105=================== ============================================================ 106 107debugfs-Interface 108----------------- 109 110=================== ============================================================ 111serial_number: unique serial number of the sensor in decimal 112=================== ============================================================ 113